1. Field of the Invention
The present invention generally relates to a fuel cell output control device, and particularly to a fuel cell output control device for driving a rotary machine.
2. Description of the Related Art
Fuel cells, which are environmentally friendly devices, are today provided on many vehicles. Because the fuel cells are not a secondary battery, they are commonly used with a high voltage accumulator to prepare for changes of load. Because it is known that the performance of such high voltage accumulators deteriorates due to overcharging or overdischarging of the accumulator, it is important to maintain an optimal power generation state of the fuel cell corresponding to various load conditions, to prevent overcharging or overdischarging of the high voltage accumulator.
For example, Japanese Patent Laid-Open Publication 2002-334712 (Patent Document 1) discloses a fuel cell system which determines a target power for running a vehicle based on an accelerator value and the like, and also determines a target power generation level for the fuel cell based on a target power of auxiliary devices, a target charge/discharge power quantity of a secondary battery, and a conversion efficiency of a DC to DC converter. In the art described in Patent Document 1, an actual measurement value is used for the conversion efficiency of the DC to DC converter to avoid any influence caused by detection errors of the power consumption of each device or the wiring resistance.